Although it is the responsibility of the motorist to check before opening their door, riding too close to parked cars (in the door zone) is still a common mistake bicyclists make that can lead to serious injury. For more information on this type of bicycle facility, visit the Sharrows FAQ.
triangle. n. 1. (Mathematics) geometry a three-sided polygon that can be classified by angle, as in an acute triangle, or by side, as in an equilateral triangle. Sum of interior angles: 180Â°; area: base Ã height. 2. any object shaped like a triangle. 3. any situation involving three parties or points of view. See also eternal triangle. 4. (Instruments) music a percussion instrument consisting of a sonorous metal bar bent into a triangular shape, beaten with a metal stick.
As you learned in the last lesson, a triangle is the simplest polygon, having three sides and three angles. The sum of the three angles of a triangle is equal to 180 degrees. Triangles are classified by sides and by angles. Move your cursor over the triangles to learn more.